1. Field of the Invention
This invention relates to a casing member with a connector portion, and more particularly to a casing member for containing an electrical equipment in a sealed condition.
2. Related Art
For example, an on-vehicle CCD (Charge Coupled Device) camera unit (which is an electrical equipment) is required to have a high degree of air-tightness (that is, high sealing ability) in order to protect this on-vehicle CCD camera unit from foreign matters such as dirt, dust and water.
Incidentally, most car batteries, mounted on vehicles, have a rated output voltage value of 12 V (volt), and there are other car batteries having their respective rated output voltage values of 24V, 36V and so on.
On the other hand, an internal operating voltage of the on-vehicle CCD camera unit is lower (for example, on the order of above 3V) in value than the output voltage of the car battery, and therefore a DC/DC converter is provided at the on-vehicle CCD camera unit, and electric power, supplied from the car battery, is converted into an internal operating voltage of the on-vehicle CCD camera unit by this DC/DC converter.
Heat is generated due to a loss developing during the voltage converting operation by the DC/DC converter of the on-vehicle CCD camera unit, and this heat much increases the temperature within a casing member containing the on-vehicle CCD camera unit in a sealed condition. Therefore, in view of a heat-radiating ability, the casing member made of metal such as aluminum has been used by preference.
There is known a technique in which an on-vehicle CCD camera unit with a connector portion is mounted in a casing member made, for example, of aluminum, and a gap between the connector portion of the on-vehicle CCD camera unit and the casing member is sealed by a sealing member (rubber plug), thereby sealing the casing member (see, for example, Unexamined Japanese Patent Publication 2002-231375).
In recent years, the amount of generation of heat from a DC/DC converter has been much reduced because of its improved voltage conversion efficiency, and it has now become unnecessary to use a metallic casing member for containing an on-vehicle CCD camera unit with such a DC/DC converter in a sealed condition.
Therefore, there has been the trend toward a technique in which a synthetic resin-made casing member for containing an on-vehicle CCD camera unit is used in order to achieve a lightweight design, the cost reduction, etc. In the development of such synthetic resin-made casing members, a study has been made of the technique of molding a connector with connection terminals (for electrical connection to an on-vehicle CCD camera unit to be contained in a casing member) integrally with this casing member. More specifically, a study has been made of the technique of forming the casing member, having a connector portion having the connection terminals, by insert molding.
However, even when the insert molding is effected, fine gaps develop between the connection terminals and the molded resin, and therefore a sealing member is provided in the connector portion (having the connection terminals) so as to be held in intimate contact with the connection terminals. In order to eliminate adverse effects of foreign matters (such as dirt, dust and water) on the on-vehicle CCD camera unit, the casing member for containing the on-vehicle CCD camera unit in a sealed condition is required to have such a high sealing ability that leakage will not occur even when the casing member is subjected to a pressure, for example, of 400 kPa.
As one example of connectors employing a sealing member, there is known one in which connection terminals extend through a sealing member in intimately-contacted relation thereto (see, for example, Unexamined Japanese Patent Publication Hei. 9-245880). In the connector disclosed in this reference, the connection terminals extend through the sealing member in intimately-contacted relation thereto, and in this condition the sealing member is mounted within a connector connecting chamber (that is, a sealing member chamber).
The connector connecting chamber of the connector has a predetermined length (that is, a depth) so as to be inserted into a mating connector while guiding this mating connector so that the male connection terminals, extending through the sealing member in intimately-contacted relation thereto, can be positively connected respectively to female connection terminals provided in the mating connector.
Therefore, when the mating connector is to be connected to the connector connecting chamber of the connector disclosed in Unexamined Japanese Patent Publication Hei. 9-245880, first, an inner peripheral wall of an open end portion of the connector connecting chamber is fitted on an outer peripheral wall of the mating connector, and the mating connector is guided by the inner peripheral wall of the connector connecting chamber, thereby positioning the two connectors relative to each other, and thereafter the connection terminals are connected respectively to the connection terminals of the mating connector. Therefore, the length of projecting of the connection terminals into the connector connecting chamber is smaller than the depth of the connector connecting chamber, and the distal ends of these connection terminals are recessed from the open end surface of the connector connecting chamber.
In the connector structure disclosed in the reference, when mounting the sealing member in the connector connecting chamber, first, the sealing member is inserted into the connector connecting chamber through the open end thereof, and then the connection terminals are passed respectively through terminal passage holes in the sealing member. Therefore, this operation has been difficult, and has required much time, so that the efficiency of the assembling operation has been low.
Particularly with respect to the sealing member designed to achieve a high sealing performance, annular lips for contact with the inner peripheral wall of the connector connecting chamber are formed on and project from the outer peripheral surface of the sealing member, and the sealing member is inserted (press-fitted) into the connector connecting chamber, with the annular lips squeezed. Therefore, the position of the sealing member within the connector connecting chamber is determined by the outer peripheral surface (that is, the annular lips) of the sealing member, and the position of the sealing member within the connector connecting chamber can not be adjusted in accordance with the positions of the connection terminals. Therefore, it has been difficult to mount the sealing member, and more specifically to pass the connection terminals through the respective terminal passage holes in the sealing member. And besides, there has been a strong possibility that the connection terminals, when forcibly inserted, damage the sealing member at their distal ends, so that the sealing performance is adversely affected.